switch intersphinx to py3.7

Author: mahmoud

docs/conf.py

@@ -76,7 +76,7 @@
 pygments_style = 'sphinx'
 
 # Example configuration for intersphinx: refer to the Python standard library.
-intersphinx_mapping = {'python': ('https://docs.python.org/2.7', None)}
+intersphinx_mapping = {'python': ('https://docs.python.org/3.7', None)}
 
 
 # -- Options for HTML output ----------------------------------------------